This invention relates to a quick coupling device and, more particularly, one used in connection with pressure fluid. For example, agricultural tractors have a quick disconnect coupling for connecting and disconnecting hydraulic hoses between the tractor and an implement. Normally, the female coupling half is on the tractor and the male coupling half is on the implement hose. Historically, both coupling halves were equipped with check valves which permitted axial flow.
Due to a closed-center valve on the tractor and a blocked circuit on the implement, conditions have been possible where internal hydraulic pressure fluid is trapped in one coupling half or even in both halves. Conventional couplings under such circumstances will not connect because the internal pressure creates a greater force than can be exerted manually to make the connection.
According to the invention, this undesirable state of affairs is avoided through the provision of a piston equipped spool in the female coupling device for contacting the male coupling check valve and establishing a generally L-shaped pressure fluid path within the female coupling. Further, the invention provides a novel seal which operates to prevent damage from high pressure build up.
Other objects and advantages of the invention may be seen in the details of the ensuing specification.